The purpose of the invention is to provide a front jaw having a compact design. A pivoting movement of the releasing one of the two angle levers also in upward direction in a predetermined degree is thereby supposed to be possible during a backward twisting fall of the skier.
Starting out from a front jaw, this purpose is attained according to the invention with the pivot axes for the two angle levers being arranged in a bearing part pivotal about a transverse axis located in an upper area of the housing on a side facing the ski boot, and with the two angle levers resting with their shorter lever arm on a vertically extending leg of a slide member loaded by the pull rod. Due to the fact that compared with the known designs only one single bearing part is needed, it is possible by using basic elements of existing front jaws to manufacture inventive front jaws, in which during a backward twisting fall the ski boot is easier released.
Actually it is already known in a front jaw having two laterally extending angle levers which grip around the sole of the boot and which are under the influence of a release spring, and a sole down-holding means between the two angle levers being arranged on a vertical adjusting screw to pivotally support the adjusting screw in a plane extending transversely with respect to the longitudinal direction of the ski and perpendicularly with respect to the upper side of the ski (see Austrian Patent No. 361 347 corresponding to U.S. Pat. No. 4,268,065). The adjusting screw is in this front jaw held by the two angle levers in the travelling or position of use so that a movement of the lower end of the adjusting screw in a slotted hole extending in transverse direction is not possible. If, however, a backward twisting fall of the skier occurs, then the lower end of the adjusting screw is released by the releasing angle lever, and the sole holder can pivot toward this side in a normal plane with respect to the longitudinal axis of the ski against a resilient element.
One of the front jaws has the advantage that after a backward twisting fall, the pivoted angle lever holds the end of the adjusting screw among others through friction, so that a return of the angle lever and of the sole holder into the position ready for stepping in is not possible (see FIG. 8). The adjusting screw is in a different one of these front jaws held in its center position by a separate spring element (see FIGS. 1-6).
The provision of two inclined surfaces in the lower area of the side of the housing, which side faces the ski boot guarantees a safe guiding of the bearing part at the start of a backward fall. The two inclined surfaces define an acute angle (.alpha.) with the upper side of the ski and on which the bearing part rests with counter surfaces in the travelling position of the front jaw.
A projection on the housing enables a safe guiding of the bearing part on the housing at the start of a backward twisting fall of the skier and a subsequent release of the bearing part therefrom enabling a pivoting of the same in a transverse plane with respect to the upper side of ski. Thus, the bearing part is blocked against a rotary movement in transverse direction until a predetermined angular position is reached.
To support the bearing part on the housing, axle journals can be provided on the bearing part, which has the advantage of being simple to mount/assemble.
An initial tension in the release spring is caused by a pull rod and during a backward fall and also during a backward twisting fall causing the bearing part to pivot, the pull rod compresses the spring. The bearing part causes less force to be required for effecting a lateral release. The friction between a further cross bar and the leg of a slide member is in a further development of this thought of the invention additionally reduced by providing a sloped surface on the further cross bar.
The provision of axle journals on the housing guarantees a surface contact of the bearing part on the housing during the entire backward fall or rather at the start of a backward twisting fall. This reduces the wear of the bearing part and the binding housing.
An inverted T-shaped recess in the bearing part assures that during a backward twisting fall of the skier, the bearing part is pivoted about an ideal axis extending in longitudinal direction of the ski only after the bearing part has already covered a predetermined path upwardly, thus a path directed away from the ski.